Past talks

We describe how a pointfree treatment of relations, their properties, their operators, and the laws that govern them can be captured in a type-directed strategic rewriting system for transformation of relational expressions. This rewriting tool can be used to simplify relational proof obligations and ultimately reduce them to tautologies. We demonstrate how such reductions provide extended static checking (ESC) for design contraints commonly found in software modeling and development.

We present an algebraic approach to transformation of structure-shy programs, in particular strategic functions (eg. Strafunski or SyB) and XML queries (eg. XPath). We formulate a rich set of algebraic laws and show how subsets of these laws can be used to construct rewrite systems for specialization, generalization, and optimization of structure-shy programs. Our approach demonstrates that the analogy between the Laplace/Fourier transforms and the point-wise/point-free transform can be extended with a structure-shy/point-free transform.

Following the work of Al-Riyami et al. we define the notion of key encapsulation mechanism supporting cryptographic workflow (WF-KEM) and prove a KEM-DEM composition theorem which extends the notion of hybrid encryption to cryptographic workflow. We then generically construct a WF-KEM from an identity-based encryption (IBE) scheme and a secret sharing scheme. Chosen ciphertext security is achieved using one-time signatures. Adding a public-key encryption scheme we are able to modify the construction to obtain escrow-freeness. We prove all our constructions secure in the standard model.

Generation and preservation of referential constraints during two-level tranformation

Luís Pedro Machado

Short introduction to the 2LT project

A two-level data transformation (2LT) consists of a type-level transformation of a data format coupled with value-level transformations of data instances corresponding to that format. A typical example of a 2LT consists in transforming XML schemas into relational database schemas, coupled with the migration of the XML documents to relational tables. Recently, we have developed a type-safe Haskell library for 2LT, based on the theory of data refinement.